More particularly, the invention concerns a rotary electrical machine, and in particular a motor vehicle alternator, having a rotor and a stator, the stator having a casing and a plurality of notches for field winding and armature winding turns, and teeth separating the adjacent notches, the said teeth each comprising a base by means of which the tooth is connected to the casing of the stator, and an end face turned towards the rotor, the end face of at least one tooth comprising at least one slot in an intermediate angular position or positions between the edges of the teeth that delimit the said notches.
The slot means here a recess whose depth in a radial direction perpendicular to the axis of the machine is greater than the width of the slot in a circumferential direction perpendicular to the axis of the machine and to the said radial direction.
French patent application FR-A-2 784 518 describes a rotary electrical machine of the aforementioned type. In the machine, the stator comprises split teeth in order to reduce the magnetic noise. In this application, the depth of a slot in a tooth of the stator in question in the radial direction is substantially equal to the maximum value corresponding to the distance between the end face and the base of the tooth, referred to as the height of the tooth.